A gas discharge display panel with mineral powder between apertured matrix and envelope seal

ABSTRACT

In a gas-discharge panel comprising a matrix inserted between two thick slabs scaled to one another by a bond surrounding the matrix, the filling of the space extending between the matrix and the bond by a mineral powder, of small glass balls for instance.

United States Patent Galves et al.

GAS DISCHARGE DISPLAY PANEL WITH MINERAL POWDER BETWEEN APERTURED MATRIX AND ENVELOPE SEAL Inventors: Jean-Pierre Galves; Henri Monfroy; Jean-Philippe Reboul, all of Paris, France Assignee: Thomson C.S.F.

Filed: Jan. 19, 1971 Appl. No.: 107,688

Foreign Application Priority Data Jan. 30, 1970 France ..700328l US. Cl. ..313/188, 313/190, 313/220, 313/221 Int. Cl ..I-I0lj 61/06, H01j 61/30 Field of Search ..313/220, 221, 210, 190, 204, 313/188; 315/169 TV [451 Dec. 19, 1972 56] References Cited UNITED STATES PATENTS 2,772,496 12/1956 Meyrick et al.. ..313/220 X 1,851,532 3/1932- Vollrath ..313/204 X 3,499,167 3/1970 Baker et al 315/169 TV 3,573,531 4/1971 Kerstetter et al. ..313/221 X 3,611,019 10/1971 Krembs ..3l3/220X Primary Examiner-Palmer C. Demeo Attorney-Cushman, Darby & Cushman I [57] ABSTRACT In a gas-discharge panel comprising a matrix inserted between two thick slabs scaled to one another by a bond surrounding the matrix, the fillingof the space extending between the matrix and the bond by a mineral powder, of small glass balls for instance.

3 Claims, 5 Drawing Figures PATENTED 3,706, 899

SHEET 1 [IF 2 The present invention relates to an improvement in gas-discharge display panels.

The problem of display signs, used in various applications for displaying a variety of results, are well known to those skilled in the art.

Those skilled in the art will appreciatethat numerous solutions have been put forward in the context of this problem, one of which consists in designing these signs in the form of gas-filled cold-cathode tubes, in which the cold cathodes, under the effect of the applied voltage, become surrounded by a sheath of light produced by ionization of the gas.

It is also known, and this more recently, to achieve such display, again by gas ionization, by using a matrix of insulating material pieced right through by holes filled with the gas in question, and, located at either side of the matrix, two networks of generally linear, conductive, electrodes, crossing over said holes,

. between the electrodes an appropriate voltage being applied in order to selectively illuminate the holes located along the character which is to be displayed.

We shall not go into the theoretical aspects of the operation of these systems known as gas-discharge display panels. These aspects are well known and have formed the subject of numerous technical literature, for example French Patent 1,522,257 assigned to University of Illinois Foundation, United States (America priority 18.1.1966).

We shall simply bear in mind, by way of information, that these devices operate either with an alternating voltage or with a direct voltage applied between the two networks of electrodes.

In these systems, there are generally provided on either side of the matrix, between the matrix and the above mentioned networks of electrodes, two insulating thin plates, of glass for instance. There are provided also, in some of the designs of the prior art, two thick slabs between which are located the matrix and the thin insulating plates, the latter being integral with either the matrix or the slabs, depending upon the technology used.

n the other hand, it ought to be pointed out that in these systems, it is necessary to seal off the gas-filled compartments vis-a-vis the exterior. This seal is generally effected by appling a peripheral bond, around and apart from the matrix, between the two slabs.

In some of the arrangements adopted in the prior art designs, the thin glass plates bear against the matrix; such arrangements are fragile, because of the necessarily small thickness of the matrix and of the glass plates in the light of the operating voltages generally employed. This fragility is obviously a major drawback.

In other arrangements of the prior art, and in order to avoid such a drawback, the thin glass plates, integral with the slabs, are kept apart from the matrix, the two slabs being spaced either by spacers specially provided at this end or by the aforesaid bond. In this case, lateral displacements of the matrix are likely to occur, which displacements are prejudicial to a satisfactory functioning of the arrangement. This is another drawback of the arrangement of the known art.

The object of the present invention is to overcome these drawbacks in particular. The present invention concerns:

A gas-discharge display panel comprising a matrix, pierced with one or several holes, on either side of said matrix two networks of linear conductors transversely disposed to each other so that a plan view of the two said networks and of said matrix exhibit intersection points located inside said hole (or holes), said matrix and networks being enclosed between two thick slabs at least one of which is transparent and projecting beyond said matrix, a peripheral bond ensuring vacum tight sealing between said slabs, said bond surrounding said matrix, and a gas enclosed in the space bounded within said bond between the two slabs, one of the slabs carrying a pumping pipe communicating with said space, characterized in that the space extending sake of clarity, the relative sizes, and specially the thicknesses, of the elements, have been disregarded.

The panel of FIGS. la and 1b is made up of a plate, for example of insulating material, or matrix] whose thickness ranges between 0.1 and 2mm and which isperforated by a network of cylindrical holes 2, referred to as cells.

Sealed to the matrix at either side of it, there are provided two thin insulating sheets 3, for example of glass, whose general thickness is far less than that of the matrix.

This arrangement is disposed between two insulating slabs 4, at least one of which, the one located at the side facing the observer made of glass for example, is transparent and has sufficient thickness to provide adequate rigidity, for example, a thickness of several mm. On each slab and on thatface which is disposed towards the interior of the panel, there is deposited a network of linear electrodes 5a and 5b. The arrangement of the assembly is such that these networks cross over the cylindrical cells. These conductive electrodes are sufficiently transparent or narrow for the light emitted by the discharge to be visible externally of the panel. In the embodiment of FIG. 1, the slabs 4 are kept apart from the thin insulating sheets 3. In this figure, the spacing between the slabs 4 and the insulating sheets 3, due to its smallness, in the order of tens of micrometers, has been enlarged for clarity. v

Gas-tightness is ensured by a peripheral annular bond 6 between the two slabs 4. This bond is produced by an enamel 7, a cement or some other material, deposited between the slabs either directly between the two, or, as the example in the Figure indicates, through the intermediary of a ring 8 surrounding the matrix. The bond 6 serves as spacer between the two slabs 4.

An orifice 9 formed in one of the slabs establishes communication with a pipe 10 which is used for pumping and, for introducing the tiller gas.

I betweentho'se parts of the electrodes which are situated beyond the matrix, there is provided all around the matrix a filling in the form of a mineral powder 11, for

example small-diameter glass balls (some few tens of micrometers), these being introduced, before pumping, through the pipe into the space between the matrix and the bond.

Pumpingis achieved through the mineral powder 1 1 and, likewise, filling with the gas at suitable pressure. I

The pipe is then sealed.

A filter 12, for example for glass-wool, located in the pipe, prevents the ing. v

Alternatively, there is provided on the same slab another pipe (not shown) similar, to pip l0, and the gas is circulated through the two pips while baking at suitable temperature, 1 I

The particles of which is made the mineral powder 11, or the glass balls, are chosen of a size larger than the spacing above referred to every time that such a spacing exists.

Large size rigid panels, for example 500 X 500 mm, can be produced in a simple manner. The slabs overlap the matrix sufficiently for the electrodes 5a and 5b located upon their faces, to be easily accessible from the exterior. A connector can then be directly wired to the ends of the slabs.

FIGS. 2, 3 and 4 illustrate three other embodiments of the invention in which figures:

FIG. 2: the thin insulating foils 3 have been replaced by insulating films 13, for example of a transparent enable deposited upon the slabs and upon the electrode networks, and bearing against the matrix 1.

FIG. 3: the matrix 1 of FIG. 1 is replaced by a frame 14, of metal for instance, located inside the bond balls from displacing during pump- FIG. 4: There are combined the two foregoing ar-' prised between the matrix and the bond 6 is filled with mineral powder 11. I

The examples described all involve the use of insulating sheets or films opposite the faces of the matrix.

It goes without. saying that the invention likewise 7 comprises variant embodiments in which the thin sheets 3 or insulating films 13 are discarded, something which would in particular be possible in'the caseof a matrix made of insulating material.

Of course, the invention is not limited to the embodiment described and shown'which was given solely by wayofexample.

What is claimed is: 1 1

1. A gas-discharge display panel comprising a matrix having a plurality of holes therein, on either side of said matrix two networks of parallelly spaced linear conductors oriented orthogonally to each other, their crossover points defining coordinate intersections in registry with said holes, two insulating elements each of. which extends between one of said networks and said matrix, said networks projecting beyond said matrix and said insulating elements, and two slabs between which are inserted said networks, said matrix and said elements, at least one of said slabs and the closer one of said two insulating elements being light transparent, a peripheral bond ensuring vacuum tight sealing between said slabs, said bond surrounding said matrix, and an illuminable gas enclosed in the space-bounded within said bond between the two slabs, the gas-being selectively illuminated by electrical signals applied to the conductors, for observation at least from one side of said panel, one of the slabs carrying a pumping pipe communicating with said space, characterized in that the space extending between saidmatrix and said bond between said slabs is filled with a mineral powder.

2. A gas-discharge display panel as claimed in claim 1 wherein the size, of the particle of which is made said mineral powder is larger than the interstices between said matrix and the other constitutive parts of said panel.

3. A gas-discharge display panel as claimed in claim 2 wherein said mineral powder consists of glass balls some few micrometers in diameter. 1

' I it 0' I 

1. A gas-discharge display panel comprising a matrix having a plurality of holes therein, on either side of said matrix two networks of parallelly spaced linear conductors oriented orthogonally to each other, their cross-over points defining coordinate intersections in registry with said holes, two insulating elements each of which extends between one of said networks and said matrix, said networks projecting beyond said matrix and said insulating elements, and two slabs between which are inserted said networks, said matrix and said elements, at least one of said slabs and the closer one of said two insulating elements being light transparent, a peripheral bond ensuring vacuum tight sealing between said slabs, said bond surrounding said matrix, and an illuminable gas enclosed in the space bounded within said bond between the two slabs, the gas being selectively illuminated by electrical signals applied to the conductors, for observation at least from one side of said panel, one of the slabs carrying a pumping pipe communicating with said space, characterized in that the space extending between said matrix and said bond between said slabs is filled with a mineral powder.
 2. A gas-discharge display panel as claimed in claim 1 wherein the size, of the particle of which is made said mineral powder is larger than the interstices between said matrix and the other constitutive parts of said panel.
 3. A gas-discharge display panel as claimed in claim 2 wherein said mineral powder consists of glass balls some few micrometers in diameter. 